HSA is a main component constituting blood plasma and is used in pharmaceutical preparations for the treatment of massive hemorrhage, shock, burns, hypoproteinemia or fetal erythroblastosis.
Currently, HSA is produced mainly as a fractionated product from collected blood. However, such a production process has problems because it is economically disadvantageous and the supply of blood is sporadic. In addition, there may a problem with the blood itself, as blood may contain undesirable substances, such as the hepatitis virus.
The recent development of recombinant DNA techniques has rendered possible the production of various useful polypeptides by microorganisms and cells, and research and development efforts have actively been made on the large scale production of HSA by means of gene manipulation techniques. However, because of low production yields, there still is an unsettled problem concerning the establishment of techniques for high purity, low cost, industrial production of HSA.
The culturing of an HSA producing host prepared by gene manipulation techniques in a medium has been carried out at 30.degree. C. when the host is a yeast strain (JP-A-3-83595 and JP-A-4-299984 corresponding to EP-A-506040; the term "JP-A" as used herein means an "unexamined published Japanese patent application").